White spot syndrome virus

White spot syndrome virus causes white spot disease, which is a highly contagious viral disease of decapod crustaceans.

These include prawns, crabs, yabbies and lobsters.

White spot syndrome virus (WSSV) or white spot disease (WSD) is not a threat to human health or food safety.

Detection in Australia

WSSV was detected and confirmed in wild caught school prawns (Metapenaeus macleayi) collected from the inshore ocean areas outside the mouth of the Evans River, Evans Head, NSW on 8 May 2024.

The prawns were collected for testing as part of annual national white spot disease surveillance activities. There were no signs of clinical disease in the tested prawns.

Since then, additional surveillance has been conducted and, on 25 May, WSSV was confirmed in a single wild prawn caught near the mouth of the Richmond River.

The NSW Department of Primary Industries (NSW DPI) is leading the response.

Testing at the CSIRO’s Australian Centre for Disease Preparedness (CSIRO ACDP) has confirmed that this strain of WSSV is the same as that detected in northern NSW in a hatchery in 2022, and in farmed prawns in 2023.

NSW movement restrictions

NSW DPI has implemented a WSSV control zone  covering the new affected area. The Evans and Richmond Rivers Control Zone includes the waters of the Evans and Richmond rivers and adjacent ocean waters 10km north of the Richmond River mouth to 10km south of the Evans River mouth. 

This is in addition to the existing Clarence River Control Zone.

Prawns and polychaete worms can only be moved out of each of the control zones  if they have been cooked.

NSW DPI is working closely with stakeholders who are affected by the control zone.

Check your state or territory’s movement and import requirements before moving seafood products across jurisdictional borders.

Meetings of the national Aquatic Consultative Committee on Emergency Animal Diseases (AqCCEAD) have been held to provide coordinated national technical discussion to assist with the NSW response.

Evans and Richmond Rivers Control Zone

Map of White Spot Control Zones in NSW

Testing and surveillance

Initial testing of samples was conducted by the NSW DPI Elizabeth Macarthur Agricultural Institute and the positive results were confirmed by CSIRO ACDP.

The CSIRO ACDP has undertaken genome sequencing of the samples and determined that the strain of WSSV is consistent with the strain detected at a hatchery in 2022 and in the white spot disease (WSD) outbreak at Clarence River prawn farms in 2023.

About WSSV and WSD

White spot disease (WSD) is caused by white spot syndrome virus. WSD is a highly contagious viral disease of crustaceans, including prawns, lobsters and crabs.

Marine polychaete worms are also considered to be vectors of the disease.

Fin fish are not affected by the disease and are not a carrier.

White spot in aquarium fish is a parasitic skin infection and not related to white spot disease of crustaceans.

White spot disease is widespread throughout prawn farming regions in Asia and the Americas where it has caused severe losses on prawn farms.

There are currently two other movement regulated areas for WSSV in Australia (the SE Qld Movement Regulated Area and the Clarence River Control Zone).

Disease signs

Signs of WSD are:

• the rapid onset of mortalities
• lethargy or unusual swimming behaviour
• cessation of feeding
• aggregations of sick or dead prawns near the water surface at the edge of rearing ponds or tanks of farmed prawns
• white spots on the carapace.

Visit outbreak.gov.au for information on how to prevent and identify white spot in farmed prawns.

Your obligations

You can help prevent the spread of WSSV and WSD.

Report sightings

Report anything unusual, even if you’re not sure.

If you suspect disease on your farm, call the Emergency Animal Disease Hotline on 1800 675 888. You’ll be directed to your state or territory government.

Recreational and commercial fishers

Steps to keep your favourite fishing spot disease free:

• Do not use seafood meant for human consumption as bait.
• Use local and reputable bait shops or source your own bait from local waterways.
• Put all unwanted seafood in a rubbish bin, not in the ocean or waterways.
• Keep your fishing gear, boat and trailer clean. Make sure that you remove bait, debris and seaweed. Check, clean and dry wheel arches on trailers, boat propellers, fishing tackle and footwear.
• Use soapy water to clean your boat and trailer, fishing rods and other equipment. Allow them to dry completely before using them at another location, even if it is on the same day.

Import conditions for prawns

We monitor and enforce stringent import conditions to manage the biosecurity risk associated with imported prawns and safeguard our valuable fisheries and aquaculture industries.

Measures to ensure Australia's import conditions are being met include pre-border and border disease testing, retail testing, and working with exporting countries.

The final report for the Review of the biosecurity risks of prawns imported from all countries for human consumption was released on 5 June 2023.

The final report proposed that prawns and prawn products can continue to be safely permitted import under the enhanced import conditions implemented in a staged approach since 2017, subject to compliance with additional strengthened biosecurity measures.

Further information about the prawn review.